 | Packaging machinery. | (1) |
| Packing-house products. | (2) |
| Packing-houses Management. | (1) |
| Packing-houses United States. | (1) |
| Packing-houses United States Design and construction. | (1) |
| Packing-houses United States Equipment and supplies. | (1) |
| Pallets (Shipping, storage, etc.) | (5) |
| Palm-oil industry Africa, West. | (1) |
| Pangolagrass. | (1) |
| Pansies. | (1) |
| Papaya United States Marketing. | (1) |
| Paper bags. | (1) |
| Paper birch. | (1) |
| Paper birch Seeds. | (2) |
| Paper industry. | (1) |
| Paper industry Northeastern States. | (1) |
| Parasitic insects. | (2) |
| Parks United States. | (1) |
| Particle board. | (1) |
| Particle board industry New Mexico. | (1) |
| Part-time farming United States. | (1) |
| Pastures. | (1) |
| Pastures Irrigation. | (1) |
| Pastures Nevada. | (1) |
| Pastures Research Nebraska Lincoln. | (1) |
| Pastures United States Fertilizers. | (1) |
| Pastures Weed control. | (1) |
| Pastures Weed control United States. | (1) |
| Pastures West (U.S.) Irrigation. | (1) |
| Peach Cooling. | (1) |
| Peach Diseases and pests. | (1) |
| Peach Handling. | (1) |
| Peach industry United States. | (1) |
| Peach Processing. | (1) |
| Peach Storage. | (1) |
| Peach United States. | (1) |
| Peanuts Composition. | (1) |
| Peanuts Handling Costs. | (1) |
| Peanuts Nutrition. | (1) |
| Peanuts Soils. | (1) |
| Peanuts Storage Costs. | (1) |
| Pear. | (1) |
| Pear Growth. | (1) |
| Peas Diseases and pests. | (1) |
| Peas Transportation. | (1) |
| Pecan Development. | (1) |
| Pecan Diseases and pests Control. | (1) |
| Penicillium. | (1) |
| Peonies. | (2) |
| Peppermint-oil United States Statistics. | (1) |
| Peppers Diseases and pests. | (1) |
| Peppers United States. | (1) |
| Pesticides. | (1) |
| Pesticides Bibliography. | (1) |
| Pesticides Costs. | (1) |
| Pesticides Environmental aspects Bibliography. | (1) |
| Pesticides Research. | (2) |
| Pesticides Toxicology Bibliography. | (1) |
| Pesticides United States Equipment and supplies. | (1) |
| Pests Control United States. | (1) |
| Phosphine. | (1) |
| Phosphorus in animal nutrition. | (1) |
| Photographic interpretation. | (4) |
| Photography, Aerial. | (2) |
| Phreatophytes Bibliography. | (1) |
| Phylogeny. | (1) |
| Physicians Washington (State) | (1) |
| Phytogeography California. | (1) |
| Phytomonas stewarti. | (1) |
| Pick your own farms New Mexico. | (1) |
| Pile drivers. | (1) |
| Pine. | (1) |
| Pine Arizona Seeds. | (1) |
| Pine Classification. | (1) |
| Pine Diseases and pests. | (1) |
| Pine Diseases and pests Control. | (1) |
| Pine Georgia. | (1) |
| Pine Growth. | (1) |
| Pine Hawaii Growth. | (1) |
| Pine Hawaii Phenology. | (1) |
| Pine Mississippi. | (1) |
| Pine Missouri. cm | (1) |
| Pine Seeds. | (2) |
| Pine Southern States. | (2) |
| Pine Sowing. | (1) |
| Pineus. | (1) |
| Pink bollworm Control United States. | (1) |
| Pipe Fluid dynamics. | (1) |
| Pitch pine Bibliography. | (1) |
| Plant-breeding Computer programs. | (1) |
| Plant cells and tissues. | (1) |
| Plant communities Oregon. | (1) |
| Plant communities Washington (State) | (1) |
| Plant diseases Congresses. | (1) |
| Plant diseases Research. | (1) |
| Plant diseases United States. | (1) |
| Plant hormones. | (1) |
| Planting time Michigan. | (1) |
| Planting time United States Statistics. | (1) |
| Plant introduction. | (1) |
| Plant introduction United States. | (1) |
| Plant layout. | (5) |
| Plant-lice. | (1) |
| Plant-lice Control. | (1) |
| Plant names, Popular. | (1) |
| Plant nematodes Handbooks, manuals, etc. | (1) |
| Plant phenology Hawaii. | (1) |
| Plant physiology. | (1) |
| Plant regulators. | (1) |
| Plants. | (1) |
| Plants as noise barriers. | (1) |
| Plants Collection and preservation. | (1) |
| Plants, Effect of air pollution on. | (1) |
| Plants, Effect of endrin on. | (1) |
| Plants, Effect of hail on. | (1) |
| Plants, Effect of heat on. | (1) |
| Plants, Effect of manganese on. | (1) |
| Plants, Effect of metals on Bibliography. | (1) |
| Plants, Effect of ozone on. | (1) |
| Plants, Effect of radioactive pollution on. | (1) |
| Plants, Effect of strontium on. | (2) |
| Plants, Effect of temperature on. | (1) |
| Plants, Effects of boron on. | (1) |
| Plants, effects of herbicides on. | (1) |
| Plants, Insecticidal. | (1) |
| Plants Nutrition. | (1) |
| Plant-soil relationships Montana. | (1) |
| Plant succession Africa. | (1) |
| Plant viruses North America Indexes. | (1) |
| Plastic containers. | (1) |
| Plum Economic aspects. | (1) |
| Plywood industry Southern States. | (1) |
| Pollution. | (3) |
| Ponderosa pine Bibliography. | (1) |
| Ponderosa pine Diseases and pests Northwest, Pacific. | (1) |
| Ponderosa pine Moisture. | (1) |
| Ponderosa pine Seeds. | (1) |
| Ponderosa pine Soils. | (1) |
| Ponds. | (1) |
| Ponds Minnesota. | (2) |
| Poor Southwestern States. | (1) |
| Poor United States. | (1) |
| Poor United States Bibliography. | (1) |
| Poplar West Virginia. | (1) |
| Population forecasting Iowa. | (1) |
| Pork Grading. | (1) |
| Pork industry and trade New Mexico. | (1) |
| Pork industry and trade Statistics. | (1) |
| Pork industry and trade United States. | (1) |
| Potatoes. | (1) |
| Potatoes Costs. | (1) |
| Potatoes Delaware Marketing. | (1) |
| Potatoes Diseases and pests. | (2) |
| Potatoes Diseases and pests Bibliography. | (1) |
| Potatoes Florida Marketing. | (1) |
| Potatoes Harvesting. | (2) |
| Potatoes Harvesting Costs. | (1) |
| Potatoes Marketing. | (2) |
| Potatoes Packing. | (1) |
| Potatoes Planting time. | (1) |
| Potatoes Transportation. | (1) |
| Potatoes United States Harvesting time. | (1) |
| Potatoes United States Marketing. | (1) |
| Potatoes United States Planting time. | (1) |
| Potato handling. | (1) |
| Potato handling Equipment and supplies. | (1) |
| Potato industry Delaware. | (1) |
| Potato industry Florida. | (1) |
| Potato machinery. | (1) |
| Potato products industry United States. | (1) |
| Poultry Breeding. | (1) |
| Poultry Diseases. | (1) |
| Poultry Feeding and feeds. | (1) |
| Poultry Feeding and feeds Linear programming. | (1) |
| Poultry Grading. | (1) |
| Poultry Housing. | (1) |
| Poultry industry Alabama Birmingham. | (1) |
| Poultry industry Netherlands. | (1) |
| Poultry industry South Carolina Greenville. | (1) |
| Poultry industry Southern States Labor productivity. cm | (1) |
| Poultry industry United States. | (2) |
| Poultry industry United States Statistics. | (1) |
| Poultry Inspection. | (1) |
| Poultry Labeling. | (1) |
| Poultry Manure Handling. | (1) |
| Poultry Marketing Research. | (1) |
| Poultry Packaging. | (1) |
| Poultry Packing. | (1) |
| Poultry plants. | (2) |
| Poultry plants Waste disposal. | (1) |
| Poultry Prices United States. | (1) |
| Poverty. | (1) |
| Power (Mechanics) | (1) |
| Precast concrete construction. | (1) |
| Precipitation (Meteorology) | (1) |
| Precipitation (Meteorology) Iowa. | (1) |
| Precipitation (Meteorology) Measurement. | (1) |
| Precipitation (Meteorology) New York (State) | (1) |
| Precipitation (Meteorology) Oklahoma Measurement. | (1) |
| Precipitation (Meteorology) United States. | (1) |
| Precipitation probabilities Iowa. | (1) |
| Precipitation probabilities United States. | (1) |
| Precipitation probabilities Wyoming. | (1) |
| Prescribed burning Environmental aspects Mississippi. | (1) |
| Prescribed burning North Carolina Carteret County. | (1) |
| Price marks. | (1) |
| Price regulations United States History. | (1) |
| Prices New York (N.Y.) | (1) |
| Prices United States. | (2) |
| Primary productivity (Biology) Measurement. | (1) |
| Produce trade. | (1) |
| Produce trade Argentina. | (1) |
| Produce trade Australia. | (1) |
| Produce trade Austria. | (1) |
| Produce trade Brazil. | (1) |
| Produce trade California Oakland. | (1) |
| Produce trade Canada. | (1) |
| Produce trade China Statistics. | (1) |
| Produce trade Colombia Statistics. | (1) |
| Produce trade Colorado Denver. | (1) |
| Produce trade Denmark. | (1) |
| Produce trade Developing countries. | (1) |
| Produce trade Developing countries Congresses. | (1) |
| Produce trade Dictionaries. | (1) |
| Produce trade Europe. | (1) |
| Produce trade European Economic Community countries Statistics. | (2) |
| Produce trade Europe, Eastern. | (1) |
| Produce trade Guatemala. | (1) |
| Produce trade Guyana. | (1) |
| Produce trade Hawaii. | (1) |
| Produce trade Hawaii Honolulu. | (1) |
| Produce trade Honduras. | (1) |
| Produce trade Hungary. | (1) |
| Produce trade Information services. | (1) |
| Produce trade Israel. | (1) |
| Produce trade Japan. | (3) |
| Produce trade Law and legislation United States. | (2) |
| Produce trade Mexico. | (2) |
| Produce trade Near East. | (1) |
| Produce trade Nigeria Statistics. | (1) |
| Produce trade Ohio Dayton. | (1) |
| Produce trade Peru. | (1) |
| Produce trade Philippines. | (1) |
| Produce trade Philippines Statistics. | (1) |
| Produce trade Saudi Arabia. | (1) |
| Produce trade South Africa. | (1) |
| Produce trade Soviet Union. | (1) |
| Produce trade Soviet Union Congresses. | (1) |
| Produce trade Turkey. | (1) |
| Produce trade United States. | (15) |
| Produce trade United States Statistics. | (3) |
| Produce trade Western Hemisphere Statistics. | (1) |
| Produce trade West Indies. | (2) |
| Pronghorn antelope. | (1) |
| Property tax Georgia. | (1) |
| Property tax Illinois. | (1) |
| Proteins in animal nutrition. | (1) |
| Protozoa, Pathogenic Identification. | (1) |
| Prune Packing | (1) |
| Pruning. | (1) |
| Psychiatric hospitals Montana. | (1) |
| Public health United States. | (1) |
| Public utilities Illinois Putnam County. | (1) |
| Public utilities United States. | (1) |
| Puccinia graminis. | (1) |
| Puccinia recondita. | (1) |
| Pulmonata Parasites. | (1) |
| Pulpwood. | (1) |
| Pulpwood industry. | (1) |
| Pulpwood Prices Southern States. | (1) |
| Pumpkin. | (2) |
| Pyrethrum (Insecticide) | (1) |